Set top box



FIG. 1 is a perspective view of the set top box showing my new design;

FIG. 2 is a front view thereof:

FIG. 3 is a top view thereof;

FIG. 4 is left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a rear view thereof; and,

FIG. 7 is a bottom view thereof.

The lines shown in dotted configuration do not make up part of the claimed design. 

The ornamental design for a set top box, as shown and described. 